Control mechanism for materials handling machines



April 14, 1959 H. A. MACKIEI 2,881,931

, CONTROL MECHANISM FOR MATERIALS HANDLING MACHINES Original Fii ed'July 10. 1953 3 Sheets-Sheet 1 FIG. I

INVENTOR.

HARRY A4 MACKIE ATTY.

April 14, 1959 H. A. MACKIE 2,

CONTROL MECHANISM FOR MATERIALS HANDLING MACHINES Original- Filed July10 1953 3 Sheets-Sheet 2 INVENTOR.

HARRY A. MACKIE ATTY.

April 14,1959 H. A. MACKIE 2,881,931

CONTROL MECHANISM FOR MATERIALS HANDLING MACHINES Original Filed July10, 1955 5 Sheets-Sheet 5 (\l v U Q 8 3 INVENTOR.

HARRY A. MACKIE United States Patent CONTROL MECHANISM FOR MATERIALSHANDLING MACHINES Harry A, Mackie, Troy Township, Wayne County, Mich.,assignor to Clark Equipment Company, a corporation or Michigan Originalapplication July 10, 1953, Serial No. 367,222. Divide? and thisapplication May 7, 1956, Serial No. 583,00

6 Claims. (Cl. 214-440) My present invention relates to stabilizingmeans for the lifting and tilting mechanisms of materials handlingmachines which have power actuated elevatable and tiltable shovels, orother load handling devices, embodied with vehicles, such as industrialtrucks, tractors and the like.

The present application is a division of my prior application, SerialNo. 367,222, filed July 10, 1953, and now abandoned.

A machine with which my present invention is particularly adapted forembodiment comprises a power actuated shovel that is arranged at theforward end of a mobile vehicle. The shovel is pivoted at the forwardend of forwardly extending arm means the latter of which is pivoted, atits rear end, to the vehicle frame. The shovel is elevated by pivotingthe arm means.

It is an object of my present invention to provide automaticallyoperable means which will, upon pivoting of the arm means, effectsynchronized tilting movement of the shovel or other load engagingdevice relative to the arm means, for maintaining the shovel in andpredetermined angular position relative to the ground.

In the accomplishment of the foregoing object, I provide a generallyinverted U-shaped synchronizer frame or yoke which is pivotally mounted,at the ends of its legs, to the arm means, about an axis common to thepivotal mounting of the shovel to the arm means. First and secondhydraulic actuating assembly means are carried by the synchronizer framewith the first assembly being arranged for tilting the shovel relativeto the synchronizer frame and arm means, and with the second assemblybeing arranged for tilting the synchronizer frame and shovel relative tothe arm means. Third hy- 'd raulic actuating assembly means is arrangedbetween the vehicle frame and the arm means, and is responsive topivotal movement of the latter.

The first and third assemblies are interconnected by hydraulic fluidlines so that the third assembly will serve to actuate the firstassembly synchronously during pivoting of the arm means, in orderautomatically to tilt the shovel relative to the arm means andsynchronizer frame, for maintaining a section of the shovel cut by agiven horizontal plane substantially parallel to the ground. Manuallyoperable valve means is provided for selective- "ly'connecting thesecond assembly with a source of fluid pressure whereby the shovel maybe tilted to any predetermined angular position relative to the ground.

Now, in order to acquaint those skilled in the art with "the manner ofconstructing and using materials handling machines in accordance withthe principles of my present invention, I shall describe in connectionwith the accompanying drawings, a preferred embodiment of my invention.

"In the drawings:

Figures 1 and 2 are side elevational views of a mobile vehicle andapower actuated shovel embodying one form of'my present invention, withthe shovel being shown in 'variousoperating positions; aportion of theshovel opcrating mechanism is cut away in both these figures in order toshow more clearly the details of this mechanism.

Figure 3 is a view taken along the line 33 in Figure 2, looking in thedirection indicated by the arrows, and shows a portion of the preferredform of my present invention; and

Figure 4 is a diagrammatic showing of the fluid circuit of the preferredembodiment of my present invention.

Referring now to Figures 1 through 4, I shall describe one embodiment ofmy present invention. A mobile vehicle or industrial truck is indicatedgenerally by the reference numeral and has a main frame 92 which at itsforward end is supported on drive wheels 94 and at its rear end onsteering wheels 96. The rear steering wheels 96 are operativelyinterconnected with the hand steering wheel 98 which is disposedforwardly of an operators seat 100.

A shovel 102 is arranged at the forward end of the truck 90. Spacedbrackets 104 are secured to the shovel 102 and are pivotally mounted ontransverse stub shafts 106 carried at the forward ends of a pair offorwardly extending arm members 108 arranged at either side of thetruck.The arm members 108 are pivotally mounted at 110 to a transverse shaftjournalled in the main frame 92.

The means for effecting pivotal movement of the arm members 108comprises a pair of movable members 112, one on each side of themachine, which are connected between the main frame 92 and one of thearm members 108. The arm pivoting means, which is indicated generally at112, comprises a cylinder 114 pivotally mounted at 116 to the main frame92, and a piston rod 118 pivotally mounted at 120 to the adjacent armmember 108.

Mounted on the stub shafts 106, which pivotally support the shovelbrackets 104, are the legs of a generally inverted U-shaped frame memberor yoke 122.

In order to effect synchronized tilting of the shovel 102 relative tothe arm members 108 as the latter are pivoted suitable means, to bedescribed hereinafter in detail, is provided for tilting the shovel 102and the yoke 122 relative to the arm members 108. Additional means areprovided for tilting the shovel 102 relative to the synchronizer frame122.

The means for effecting tilting of the shovel 102 relative to thesynchronizer frame 122 and the arm members 108 comprises an hydraulicactuating assembly indicated generally by the reference numeral 124. Theassembly 124 comprises a cylinder 126 pivotally connected at 128 to thebight portion of the U-shaped frame 122, and a piston rod 130 pivotallyconnected at 132 to a bracket 134 which is secured to the shovel 102.

The means for tilting the synchronizer frame 122 and the shovel 102relative to the arm members 108 comprises hydraulic actuating assemblies136 and 138 each of which includes a pair of relatively movable members.The assembly 136, which is arranged at one side of the truck, comprisesa cylinder 140 pivotally mounted at 142 to the main frame 92, and apiston rod 144 pivotally mounted at 120 to the adjacent arm member 108.The assembly 138 comprises a cylinder 146 pivotally mounted at 148 tothe bight portion of the U-shaped frame 122, and a piston rod 150pivotally mounted at 152 to a lever 154 secured to a member'156 fixed atits ends to the arm members 108.

Referring now to Figure 4, I shall describe the fluid circuit which isassociated with the aforedescribed hydraulic actuating assemblies 112,124, 136 and 138. The fluid circuit comprises a source of fluid pressure158 the pressure side of which is connected, through a fluid line 160,with three valve assemblies indicated generally by the referencenumerals 162, 164 and 166, which, re-

spectively, are provided with control levers 168, and

17 2. A fluid return line 174 interconnects the valves 162,

the lines 176 and 178, and the valve 164 and the lines 180 1 and 182 areso arranged that when one line of each pair is under pressure, the otherline of each pair is under bleed. An additional pair of fluid lines 184and 186 interconnect the valve 166 with the cylinders 140 and 146 of thesynchronizer frame tilting assemblies 136 and 138.

In the operation of my invention, after a load has been engaged by theshovel 102, fluid under pressure may be,

by actuation of the control lever 170, selectively admitted through thefluid line 180, to the upper end of the cylinder 126 of the tiltassembly 124 for distending the piston rod 130 and causingcounter-clockwise pivotal movement of the shovel 102. After the shovel102 has. been tilted from the load engaging solid line position, shownin Figure 1, to the load carrying position shown in dot-dash lines, theshovel 102 may be elevated by pivoting the arm members 108. Such pivotalmovement of the arm members 108 may be effected by actuating the controllever 168 of the valve 162 for admitting fluid under pressure, throughthe fluid line 176, to the left end of the cylinder 114 of the elevatingactuating assembly 112.

In order to maintain the shovel 102 in a predetermined angular positionrelative to the ground, during elevation of the shovel 102, thehydraulic actuating assemblies 136 and 138 are operable for effectingsynchronized tilting of the synchronizer frame 122 and shovel 102relative to the arm members 108.

The described synchronized tilting is effected through the actuating ofthe assembly 136 by the pivoting of the arm members 108. Duringclockwise pivoting of the arms 108, the piston rod 144 is urgedoutwardly of the cylinder 140, and pressure is thereby exerted on thefluid in the line 186 causing fluid flow therethrough to the lower endof the cylinder 146. Such fluid flow causes the piston rod 150 to moveupwardly for tilting the shovel counterclockwise. Simultaneously, fluidis moved from the upper end of the cylinder 146, through the line 184,to the right end of the cylinder 140. If the piston rod 144 is urgedinwardly, upon counter-clockwise movement of the arms 108, as when thearms are pivoted upwardly, will be forced through the lines 184 and 186in a reverse direction for I tilting the shovel clockwise.

Fluid under pressure may be selectively admitted initially to thesynchronizer fluid lines 184 and 186 through suitable manual actuationof the control lever 172 of the valve 166. The valve 166 is furtheroperable for supplementing the fluid in the lines 184 and 186, tocompensate for leakage therefrom, and for changing the position of thesynchronizer frame 122 relative to the arm members to the lower end ofthe cylinder 126 of the tilt actuating assembly 124 for retracting thepiston rod 130. Retraction of the piston rod 130 effects clockwisepivotal movement of the shovel 102 relative to the synchronizer frame vwhich will, upon pivoting of the arm members, effect synchronizedtilting movement of the shovel relative to the arm members formaintaining the shovel or other load handling device in anypredetermined angular position relative to the ground. It will befurther observed that not only is the mechanism of my present inventionsimple in structure and efiicient in operation, but it is also inex- 4pensive and may be readily adjusted for v of operation.

Now while I have shown and described what I believe to be a preferredembodiment of my present invention, it will be understood that variousmodifications and rearrangements may be made therein without departingfrom the spirit and scope of my invention.

I claim:

1. For use with a vehicle having a main frame, the combination of a loadhandling device, forwardly extending arm means pivoted at the rear endto the vehicle frame and at the forward end to said device, poweractuated means carried by the vehicle and having connection with saidarm means for effecting pivotal movement of the latter whereby saiddevice may be raised and lowered, a synchronizer member carried by saidarm means, first and second hydraulic actuating assembly means connectedto said synchronizer member for tilting said load handling devicerelative to said arm means, manually operable means for effectingactuation of said first hydraulic actuating assembly means, thirdhydraulic actuating assembly means between said main frame and said armmeans and responsive to pivotal movement of the latter, and said secondand third hydraulic actuating assembly means being interconnected byfluid lines whereby said third hydraulic actuating assembly means servesto actuate said second hydraulic actuating assembly means duringelevaarious conditions tion of said device so as to tilt automaticallysaid device relative to said arm means for maintaining a section of thedevice cut by any given horizontal plane substantially parallel to theground.

2. For use with a vehicle having a main frame, the combination of ashovel, forwardly extending arm means pivoted at the rear end to thevehicle frame and at the forward end to said shovel, power actuatedmeans carried by the vehicle and having connection with said arm meansfor effecting pivotal movement of the latter whereby said shovel may beraised and lowered, a synchronizer frame pivotally mounted to said armmeans about an axis common to the pivotal mounting of said shovel tosaid arm means, first means carried by said synchronizer frame fortilting said shovel relative to said synchronizer frame and said armmeans, second means carried by said synchronizer frame for tilting saidsynchronizer frame and said shovel relative to said arm means, manuallyoperable means for effecting actuation of said first shovel tiltingmeans, and means responsive to pivotal movement of said arm means foreffecting actuation of said second shovel tilting means whereby saidsynchronizer frame and said shovel are automatically tilted relative tosaid arm means during elevation of said shovel for maintaining a sectionof the shovel cut by any given horizontal plane substantially parallelto the ground.

3. For use with an industrial truck having a main frame, the combinationof a shovel, forwardly extending arm means pivoted at the rear end tothe truck frame and at the forward end to said shovel, power actuatedmeans carried by the truck and having connection with said arm means foreffecting pivotal movement of the latter Where'- by said shovel may beraised and lowered, first and second hydraulic actuating assembly meanscarried by said arm means for tilting said shovel relative to said armmeans, third hydraulic actuating assembly means between said main frameand said arm means and responsive to pivotal movement of the latter,first, second and third four-way valves, a source of fluid pressure, apair of fluid lines between said source of fluid pressure and saidfirst, second and third four-way valves, one line constituting apressure line and the other constituting a return line, a pair of fluidlines between said first four-way valve and said power actuated meanswhereby the latter may be actuated selectively for effecting pivotalmovement of said arm means,

draulic actuating assembly means may be adjusted selectively, said thirdhydraulic actuating assembly means serving to actuate said firsthydraulic actuating assembly means during elevation of said shovel sothat said shovel is automatically tilted relative to said arm means formaintaining a section of the shovel cut by any given horizontal planesubstantially parallel to the ground, and a pair of fluid lines betweensaid third four-way valve and said second hydraulic actuating assemblymeans whereby the latter may be actuated selectively for effectingtilting of said shovel relative to said arm means.

4. In a vehicle having a main frame, the combination of a load handlingdevice, outwardly extending arm means pivoted to the vehicle frame andhaving said device pivotally supported thereon near the outer end of thearms, power actuated means carried by the vehicle and having connectionwith said arm means for effecting pivotal movement of the latter wherebysaid device may be raised and lowered, a synchronizer frame membercarried by said arm means and first and second fluid means connected tothe said synchronizer frame member for tilting said device relative tosaid arm means, manually operable means for selectively effectingactuation of said first fluid means whereby said device may be tilted,and means responsive to pivotal movement of said arm means for effectingactuation of said second fluid means whereby said device isautomatically tilted relative to said arm means during elevation of saiddevice for maintaining a section of the device cut by any givenhorizontal plane substantially parallel to the ground.

5. In a materials handling machine having pivoted outwardly extendingarm means, a load handling device pivotally connected to the arm meansnear the outer end thereof, and power actuated means for pivoting thearm means to raise and lower the load handling device, the

combination of a synchronizer frame pivotally mounted on the arm meansnear the outer end thereof, a first hydraulic actuator connected betweensaid synchronizer frame and the load handling device for selectivelytilting the latter, a second hydraulic actuator connected between saidsynchronizer frame and the arm means, and an hydraulic device operatedby the arm means during raising and lowering operation thereof forsupplying hydraulic fluid to said second actuator for automaticallytilting said synchronizer frame and the load handling device relative tothe arm means during raising and lowering of the arm means formaintaining the synchronizer frame and load handling device in aselected position relative to the ground during such raising andlowering operation.

6. In a materials handling machine having pivoted outwardly extendingarm means and a load handling device pivotally connected to the armmeans near the outer end thereof to be raised and lowered by pivotingoperation of the arm means, the combination of a member carried by thearm means and two fluid actuators connected to the said member andarranged to tilt the load handling device, manual means for selectivelyoperating a first one of said actuators for tilting the load handlingdevice, and a fluid device responsive to pivoting movements of the armmeans for supplying fluid to the second said fluid actuator forautomatically tilting the load handling device relative to the arm meansduring pivoting operation of the arm means to raise and lower the loadhandling device.

References Cited in the file of this patent UNITED STATES PATENTS2,613,822 Stanley Oct. 14, 1952 2,620,930 Mullgardt Dec. 9, 19522,731,162 Walstrom Ian. 17, 1956 UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION Patent NO. 2,881,931 April 14, 1959 Harry A. Mackie It ishereby certified that error appears in the-printed specification of theabove numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 1, line 27, for 'at the read to the line 35 for in and" read inany column 3, line 47, after 'upwarc'1ly,," insert fluid Signed andsealed this 28th day of July 1959.

(SEAL) Attest:

KARL H. AXLINE Attesting Ofiicer ROBERT C. WATSON Commissioner ofPatents

